Containers for fragile articles



May 11, 19 5 p. MAIO CONTAINERS FOR FRAGILE ARTICLES 3 Sheets-Sheet 1 Filed Nc w. 15, 1962 INVENTOR Par/"c Mfl C I VATITZZNEY- May 11, 1965 P, MAIO CONTAINERS FOR FRAGILE ARTICLES led Nov. 15, 1962 s sheets-sheet 2 INVENTOR an? aw M410 BY I AT Q NEY.

May 11, 1965 P. MAIO 3,182,885

' CONTAINERS FOR FRAGILE ARTICLES v I Filed Nov. 15, 1962 3 Sheets-Sheet, 3

INVENTQR Var/9K1: /Yn/o.

3,182,885. CONTAINERS FOR FRAGILE ARTICLES Patrick Maio, Wood-Ridge, NJ., assignor to Continental This invention relates generally to containers for fragile articles, such as, electronic tubes and the like.

An object of the invention is to provide a one-piece cardboard container for an electronic tube or other fragile article comprising a box thatmay be shipped and stored in the fiat condition and'has a cushioning structure therein which, in the erected condition of the box, is adapted to engage an electronic tube or other fragile article inserted therein and thereby protect the latter against'shocks to which the outer box is subjected.

In accordance with an aspect of this invention, a onepiece cardboard-container for a fragile article comprises four foldably connected side walls angularly movable between a substantially flat collapsed condition and an erected condition where the side walls define a box withright angled corners having end closuresconstituted by the usualfiaps hingedly extending from the end edges of the side walls, and a cushioning structure in the box including wall portions hingedly connected to two opposed side walls of the box at locations spaced from the corners of the latter so as to be-spaced from each other and extend away from the side walls of the box in the erected condition of the latter, wherebyan electronic tube or other fragile article inserted between the wall portions of the cushioning-structure is heldby the latter out .of contact with the side walls of the box and thereby cushioned against shocks to which the box may be subjected. In one embodiment of the invention, thev wall portions of the cushioning structure extend between the two opposed side walls of the box to which they are hingedly connected, and such wall portions are parallel to each other and to the other side walls of the box,'with each of the parallel wall portions of the cushioning structure havand movable relative to the wall portion about parallel hinge lines'to be pressed outwardly toward 'the adjacent side walls of the box by an article placed between the iinited? States Patent ill - ing elongated, opposed flaps struck or die-cut therefrom wall portions of the cushioning structure and having a lateral dimension or diameter greater than the distance between the wall portions. Further, the flaps struck from the wall portions of the cushioning structure terminate short of the ends of the latter so that, when an article .presses the flaps outwardly,'the article is held against longitudinal displacement by the edges of the wall portions at the ends of the flaps. I

In order to cushion the electronic tube or other fragile article at one or more of its ends, as well as at the sides thereof, 'each of the wall portions of the cushioning structure further has a tab struck therefrom at least adjacent one end of the flaps, which tab is movable relative to therespective wall portion about a hinge line at right angles to the hinge lines of the flaps so as to be adapted to extend inwardly toward the tab of the other wall portion and thereby cooperate to cushion an end of the article disposed between'the'wall portions with respect to the adjacent endclosure of the box. 'Each of the tabs is preferably integral with an extension struck from the same wall portion and-.s wingable relative to the wallportion about the same hinge line as the tab, but in the opposite direction, so that the extension is pressed out wardlyby the article between the wall portions and thereby urges the related tab inwardly.

:line 8--8 on FIG. 7;

3,182,885 Patented May 11, 1965 In order to further secure cushioning of an end .or ends" of the fragile article, the tabs may be dimensioned to normally extend beyond the adjacent ends of the wall portions of the cushioning structure so that, when the flaps at the ends of the box are folded to form the end closures, the end closures bear against the tabs and cause inward bowing of the latter.

In another embodiment of the invention, the locations at which the wall portions of the cushioning structure are hingedly connected to the two opposed side walls, of the foldable box are adjacent the diagonally related corners of the box which are furthest from each other in the collapsed condition of the box, and the'wall portions of the cushioning structure are foldable in opposite directions about medial lines thereof to move away from each other during erection of the box and thereby embrace an article placed between the wall portions of the cushioning structure. The distances from the medial lines of the wall portions of the cushioning structure to the locations where the wall portions are hingedly connected to the side walls of the box are preferably smaller than the width of the sidewalls of the box so that, in the erected condition of the box, the wall portions of the cushioning structure are skewed. or obliquely related to the side walls of the box, thereby to hold a fragile article embraced by the cushioning structure out of contact with the side walls of the box. In this embodiment of the invention, the cushioning structure may be substantially coextensive with the side walls of the box in the longituf dinal direction of the latter, or the cushioning structure may extend longitudinally only along approximately onehalf of the length of the box, thereby to reduce the quantity of cardboard stock required for production of the container.

A further feature of the last described embodiment of The above, and'other objects, features and advantages of the invention, willbe apparent in the following detailed description of illustrative embodimentsfthereof which is to beread in connection with the accompanying drawings, forming a part hereof, and wherein:

FIG. 1 is a plan view of a blankfrom which a container embodying the present invention may be formed;

FIG. 2 is a perspective view, partly broken away, of a container formed from the blank of FIG. 1, but shown on an enlarged scale;

. FIG. 3 is a transverse sectional view of the container taken along the line 3-3 on FIG. 2; FIG. '4 is a fragmentary, vertical sectional view of the upper portion of the container of FIG. 2, but shown with the upper .end flaps'closed to form an end closure for I the box;

' FIG. 5 is a view similar to that of FIG 4, but illustrating a modification of the container of FIG. 2;

FIG. 6 is a plan view of a blank from which a container constructed in accordance with another embodiment of this invention'may be formed;

FIG. 7 is a perspective view, partly "broken away, of a container formed from the blank of FIG. 6, but on an enlarged scale;

FIG. 8 is a transverse sectional .view taken along the FIG. is a perspective view, partly broken away, of

a container formed from the blank of FIG. 9, but on an enlarged scale; and

FIG. 11 is a transverse sectional view taken along the line 1111 on FIG. 10.

Referring to the drawings in detail, and initially to FIG. 1 thereof, it will be seen that a fiat, one-piece blank 10 of cardboard stock which is die-cut so as to permit the forming therefrom of a container embodying this invention generally includes a box defining section 12 and a section 14 for defining the cushioning structure within the. box.

The box defining section 12 includes four rectangular side wall defining portions 16, 18, and 22 of substantially equal areasv joined successively to each other along fold lines 24, 26 and 28, respectively. The section 12 of the blank 10 further includes end flap defining portions 30 and 32 extending from the opposite ends of the side wall defining portions 18 and 22, respectively, and joined to the latter along fold lines 34 and 36. The flap defining portions 30 and 32 at one end of side wall defining portions 18 and 20 are intended to form an end closure of the box together with an end wall defining portion 38 extending from the adjacent end of the side wall defining portion 20 and joined to the latter along a fold line 40, while the flap defining portions 30 and 32 at theother ends of the side wall defining portions 18 and 22 are intended to form the other end closure of the box together with an end wall defining portion 38 joined along a fold line 40 to the adjacent end of side wall defining portion 16. The end wall defining portions 38 have tab defining portions 42 joined to their outer ends along fold lines 44. The box defining section 12 of blank 10 is completed by a narrow elongated portion 46 joined along a fold line 48 to the longitudinal edge of portion 22 remote from portion 20.

The section 14 of the blank which is intended to form the cushioning structure of the container embodying this invention includes a generally rectangular wall defining portion 50 joined, at a fold line 52 extending along one of its longitudinal edges, to the portion 46 of section 12 and further joined, at a fold line 54 extending along its opposite longitudinal edge, to a rectangular connecting portion 56. A wall defining portion 60 which is the mirror image of the portion 50 is joined, at a fold line 58 extending along one of its longitudinal edges, to the side margin of connecting portion 56 remote'from portion 50, and an elongated flap 62 is joined along a fold line 64 to the side margin of wall defining portion 60 remote from connecting portion 56. The wall defining portions 50 and 60 of section 14 of the blank each have a width substantially equal to the width of the side wall defining portions 18 and 22 of section 12, while the connecting portion 56 has a width substantially smaller than the width of the side wall defining portions 16 and 20.

Each of the wall defining portions 50 and 60 has a longitudinal, centr-allylocated slit 66 formed therein between transversely extending cuts 68 and 70. The transverse cuts 68 and 70 terminate short of the longitudinal margins of the portions 50 and 60, and fold lines 72 are formed between the ends of the transverse cuts 68 and 70, so that elongated, opposed flaps 74 are defined by the slit 66, the transverse cuts 68 and 70 and the fold lines 72 of each of the portions 50 and 60.

If desired, the central slit 66 may be extended at one end beyond the transverse cut 70 to another transverse cut 76 which .is shorter than the cut 70 and has its ends joinedto the adjacent ends of the fold lines 72 by converging fold lines 78 to define opposed tabs 80.

At the end of the elongated flaps 74 remote from the tabs 80, eachof the wall defining portions 50 and 60 is formed with short cuts or slits 82 as extensions of fold lines 72, that is, extending from the ends of transverse cuts 68, to the outer ends of relatively short, transversely extending fold lines 84. The inner ends of fold lines 84 meet the ends of a U-shaped cut 86 which defines a tab 88 adapted to be struck from each of the wall defining portions 50 and 60. The cuts 68 and 82 and the fold lines 84 define an extension 90 which is movable with the adjacent tab 88 about the fold lines 84 but in the opposite direction.

In the following description of the container 10a of FIG. 2 formed from the blank 10, the several parts thereof are identified by the reference numerals employed in describing the corresponding portions of the blank, but with the letter a" appended thereto.

In forming the container illustrated on FIG. 2 from the blank 10 of FIG. 1. adhesive is first applied to the portions 56 and 62 at one surface of the blank and to the portion 46 at the opposite side or surface of the blank. The tab portion 62 of blank 10 is turned about fold line 64 relative to wall defining portion 60 so as to lie on the latter with the adhesive bearing surface of tab portion 62 at the outside. Wall defining portion 50 is turned about fold line 54 relative to connecting portion 56 so as to overlie the latter and part of wall defining portion 60, and portion 46 is turned about fold line 52 so as to extend in the direction away from tab portion 62 so that the adhesive bearing surface of portion 46 also faces outwardly. Thereafter, side wall defining portion 20 is folded about fold line 28 to underlie portion 56, with the adhesive bearing surface of the latter engaging centrally against the inner surface of portion 20. Finally, portion 16 is folded about fold line 24 to overlie and be adhesively secured to portions 62 and 46.

After the above described folding of the blank 10, the resulting container 10a is in a collapsed or flattened condition and can be erected merely by angularly displacing the portions 16 and 22 of the blank away from the portions 18 and 20, respectively. The erected container includes a box 12a having foldably connected side walls 16a, 18a, 20a and 22a, with the longitudinal edge portion of side wall 16a which is remote from side wall 18a being secured to the portion 46a by the adhesive on the outer surface of the latter. The box 12a is provided with conventional end closures (FIG. 4) in the'form of is withdrawn, the box 12a may again be folded flat or collapsed.

Within the erected box 12a, the container 10a includes a cushioning structure 14a made up of parallel, spaced apart wall portions 50a and 60a extending between the connecting portion 56a which is adhesively secured to side wall 20a and portions 46a and 62a, which are adhesively secured to the opposite side wall 16a. It will be apparent that the wall portions 50a and 60a of the cushioning structure extend parallel to the side walls 18a and 22a of the box and are spaced from such side walls in the erected condition of the box. wall portions 50a and 60a are hingedly connected to walls 16a and 20a at lines spaced from the corners of the box 12a.

The container 10a is dimensioned so that, in its erected condition, the distance between the wall portions 50a and 60a of its cushioning structure is substantially less than the diameter of the electronic tube or other fragile article to be inserted in the container, as indicated by broken lines at T on FIG. 3 Thus, when an electronic tube T is inserted between the wall portions 50a and' 60a of the cushioning structure, the tube pushes out the flaps 74a of the wall portions so that the edges of the flaps may bear against the adjacent side walls 18a and 22a (FIG. 3) thereby to cushion the tube T with re- Further, the

. spect to the side walls 180 and 22a of the outer box and'further to locate the tube out of contact with the other side walls 16:: and 20a.

As shown on FIG. 4, the upper or domed end of the tube T also acts outwardly against the extensions 90a of the wall portions 50a and 60a and thereby causes inward swinging of the related tabs 88a to cushion the tube and prevent contact of the latter with the adjacent end closure of the box. Further, the lower or base end of the tube acts outwardly against the tabs 800 so that the 'base of the tube or other fragile article rests on the edges of wall portions 50a and 60a corresponding to the transverse cut 76 of the blank. Thus, if after insertion of the electronic tube in the container a, the end closure appearing at the top of the container in FIG. 2 is adhesively or otherwise secured in its closed condition, then the container 10a is substantially pilfer-proof, in that the tube cannot be withdrawn from the opposite end of the container without causing substantial destruction of the container, or at least of the cushioning structure 14a thereof. This pilfier-proof feature of the container 10a ensures against the substitution of used articles for the new articles originally packaged in the box or container.

It will be apparent that the cushioning structure 14a of the above described container 10a supports the electronic tube or other fragile article out of contact with all four side walls of. the box 12a and also out of contact with'both of the end closures of the box, and thereby protects the tube or fragile article against damage by shocks to which the outerbox is subjected. It is also apparent that the container 10a maybe shipped and stored in its fiattenedor collapsed condition and only erected to the condition or position of FIG. 2 at the time when a tube or' other fragile article is to be inserted therein. 1

Referring now to FIG. 5, it will be seen that the modified container 10b illustrated therein is generally similar to the previously described container 10a and has its several par-ts identified by the reference numerals used to identify the corresponding parts of container 10a, but with the letter b appended thereto. In the container 10b of FIG. 5, the tabs 88b of the cushioning structure ex- 1 tend beyond the adjacent ends of the wall portions 50b and 60b so that, when the flaps 30b and 32b and the end 'wall 38b are folded to form the end closure at the adjacent endqof the box 12b, such end closure acts upon the ends of the tabs 88b to further urge the latter inwardly toward each other and there-by positively ensure against contact of the upper end' of the tube'T with the adjacent end of the box.

Although the containers 10a and 10b have been shown as having the tabs 88a and 88b adjacent only one end of the cushioning structure, it is apparent that such tab may be, provided at both ends of the cushioning structure for-similarly providing cushioned support for the tube or other fragile article at the opposite ends of the latter.

, Referring now to FIG. 6, it will be seen that a flat blank 101 of cardboard stock for forming a container in accordance with another embodiment of this invention may include a box defining section 12 which is substantially the same as the box defining section of the previously described blank 10 and which has its respective portions identified by the same reference numerals. The flaps 30 and 32 may extend from the side wall defining portions 16 and 20, as on FIG. 6, or from the side wall defining portions 18 and 22, as on FIG. 1, and the end wall defining portions 38 may extend from the side wall defining portions 18 and 22, as on FIG. 6, or from the sidewall defining portions 16 and 20, as on FIG. 1.

The blank-101 of FIG. 6 further has a section 114 intended to define the cushioning structure of the container and generally including a rectangular" portion 92 joined to the portion 46 of section 1'2 "along a fold line to the fold line 94 with the distances bet-ween the fold lines 94 and 96 and the fold lines 96 and 98 being equal and each lessthan the width of the side wall defining portions 16, 18, 20 and 22. Between the fold line 98 and the adjacent longitudinal edge of rectangular portion 92 there is defined an elongated fiap defining portion 100,

between cuts 104 and 106 and wall defining portions 110 and 112 extending from the cuts 104 and 106, respectively, to the adjacent end edges of rectangular portion 92.

In forming a container from the blank 101 of FIG. 6, adhesive is applied to the portions 46 and 100 "at one surface of the blank, and to the tab 102 at the opposite surface of the blank. Thereafter, the blank is folded to produce the container 101a of FIGS. 7 and 8, in "which the several parts are identified by the reference numerals used in connection with the corresponding parts of the blank, but with the letter a appended thereto. In folding the blank 101, the flap 100 is initially folded about the fold line 98 so that the adhesive bearing surface of 'flap 100 faces outwardly, while the adhesive bearingsurface of tab 102 contacts the central wall defining portion 108' at one side of the fold line 96. Thereafter, side wall defining portions 22 and 20 are folded together about fold line 48 in the direction away from the adhesive bearing surface of portion 46, so that the adhesive on flap 100 engages the surface of side wall defining portion 20, and sidewall defining portions 18 and 16 are then folded together about fold line 26 so that the free longitudinal edge portion of portion 16 is engaged by the adhesive on portion.

The resulting collapsed or flattened container is erected by angularly displacing the walls 20a and 22a away from the walls 16a and 18a of the box 12a. During such erection of the box, the wall portions 110a and 112a of the cushioning structure 114a are folded in one direction about their medial lines 96a',-while the central wall portion 108a is made to fold in the opposite direction about its central or medial line 96a by reason of the adhesive attachment of the wall portion 108a to the tab 102a extending from flap 100a which is adhesively secured toseen that such hinged connections 94a and 98a are spaced 94. The rectangular portion 92 has parallel, spaced from the corners of the erected box 12a, but are relatively close to the diagonally opposed corners defined between the side walls 16a and 22a and the side walls 18a and 20a, respectively. Further, since the distances between the medial line 96a of the wall portions 108a, 110a and 112a and the hinge lines 94a'and 980, respectively, are smaller than the width of each of the side walls of box 12a, the

wall portions 108a, 110a and 112a of the cushioning structure are skewed or obliquely arranged with respect to the side walls of the outer box 12a in the erected condition Thus, the wall portions of the with reference to FIGS. 6, 7 and 8, may extend substani tiallyalong the entire length of the box of the container, -as'in -the case of the cushioning structure114a,.or the only extending along approximately one-half of the length of the elongated portion 46 of the blank section 12. The various portions of the section 114' are identified by the same reference numerals as the corresponding portions of the section 114, but with a prime being appended to each reference numeral. Thus, the shortened section 114' includes wall defining portions 108', 110 and 112 divided by the cuts 104' and 106', a flap defining portion 100' extending from the wall defining portions along a fold line 98, and a tab defining portion 102 extending centrally from the flap 100'. Further, the section 114 of blank 101 preferably includes a leg defining portion 104 extending from fiap 100' along a fold line 106 at one side of the tab 102' and terminating in a foldable tab defining portion 108.

In forming the container 101'a of FIGS. 10 and ll from the blank 101' of FIG. 9, adhesive is initially applied to the tabs 102 and 108, at one surface of the blank, and to the flap 100 and portion 46 of the blank, at the other surface of the blank. Thereafter, the blank 101 is folded in the manner previously described with respect to the blank 101 of FIG. 6. Thus, during the initial folding of the fiap 100 about the fold line 98', the tab 102' is adhered to the wall defining portion 108', at one side of the fold line 96, while the tab 108 at the end of leg 104 is adhered to the wall defining portion 110 at the opposite side of the fold line 96'.

Upon erection of the container, as in FIGS. 10 and ll, the leg 104a extends laterally across the lower part of the cushioning structure l14a between the edge of the flap 100'a secured to the side wall a of the box and the wall portion 11'0a of the cushioning structure. Thus, a tube T represented by broken lines on FIG. 11, may be inserted in the cushioning structure where it is embraced by the wall portions 108'a and 112'a, and thus held out of contact with the side walls of the box 1211, while the base or lower end of the tube rests on the laterally extending leg 104a so as to be held out of contact with the lower end closure of the box.

In cutting successive blanks 101' from a strip or sheet of cardboard stock, it will be apparent thatthe section 114' of one blank may be arranged next, or nested with respect to the section 114' of another blank, thereby to reduce the quantity ofcardboard stock required for the several blanks.

It will also be apparent that the blank 101 of FIG. 6, in which the section 114 for defining the cushioning structure of the container extends along substantially the entire length of the box defining section 12, may also be provided with a leg defining portion, similar to the portion 104 of the blank 101', and extending from the fiap forming portion 100 at a location in lateral alignment with the wall defining portion 110 of section 114 so that the of the box, thereby to cushion the article against shocks or impacts to which the box is subjected.

Although illustrative embodiments of the invention have been described 7 in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein without departing from the scope or spirit of the invention, except as defined in the appended claims.

What is claimed is:

1. A one-piece cardboard container for a fragile article comprising four foldably connected side walls angularly movable between a substantially flat collapsed condition and an erected condition where said side walls define a box with right angled corners, and cushioning means in said box including a pair of wall portions extending between, and being hingedly connected to two opposed side walls of said box at locations spaced from the corners of the box so as to be spaced from each other and extend away from said side walls in the erected condition of the latter, said wall portions being parallel to each other and to the other two side walls of the box, each of said wall portions having elongated, opposed flaps struck therefrom and movable relative to the -wall portion about parallel hinge lines to be pressed outwardly toward said other two side walls by an article inserted between, and cushioned by said wall'portions, said flaps terminating short of the ends of the related wall portion of the cushioning means so that, when an article presses the flaps outwardly, the article is held against longitudinal displacement by the edges of said wall portions at said ends of the flaps, each of said wall portions further having a tab struck therefrom at least adjacent one end of said flaps and an integral extension of said tab disposed between the latter and said flaps of the related wall portion, said tab and its integral extension being jointly swingable about a hinge line located therebetween and extending at right angles to said hinge lines of the flap so that an article disposed between said wall portions also presses outwardly the extensions of the tabs thereby to urge the latter inwardly toward each other for cushioning an end of an article between said wall portions with respect to the adjacent end of the box.

2. A one-piece cardboard container as in claim 1; wherein said tabs normally extend beyond the adjacent ends of said wall portions, and said box has end closures to bear against said tabs and cause inward bowing of the latter for increasing the cushioning of the adjacent end of an article.

3. A one-piece cardboard blank for forming a shockproof container for a fragile article; said blank comprising a box defining first section including four foldably connected, substantially rectangular side wall forming portions in side-by-side relationship, end closure forming flaps extending foldably from theends of certain of said side wall forming portions, and an elongated narrow portion extending along one side of said box defining section and foldably joined to the adjacent side wall forming portion of the latter; and a second section for defining a cushioning structure extending foldably from said elongated narrow portion of the box defining first section and including two foldable, rectangular wall defining portions, a concushioning structure 114a of the resulting container shown on FIG. 7 will also have a laterally extending leg at the bottom of the cushioning structure to hold a tube or other fragile article embraced by'the cushioning structure out of contact with the lower end closure of the box 12a.

It will further be noted that the several described em-- bodiments of the invention are all characterized by the necting portion interposed between said two wall defining portions and foldably joined to the latter and a fiap defining portion at' the side of said second section remote from said first section; each'of said two wall defining portions having a central, longitudinally extending cut and transverse cuts at the ends of the longitudinal cut to define two opposed, elongated fiaps adapted to be struck from the related wall defining portion; and each of said two wall defining portions further having short cuts extending longitudinally from the ends of at least one of said transverse cuts and a generally U-shaped cut between said short cuts and extending in the direction toward said one transverse cut to define a tab adapted to be struck from the related wall defining portion for movement angulariy with, butin the opposite direction from the part of the wall defining portion located between said short cuts.

Referenees Cited by the Examiner UNITED STATES PATENTS f 5 10/35 Mertz 206-77 8/38 Weil 206-4514 4/45 Freei et a1. 206-4519 7/50 Tyseck 229-14 12/50 Tyseck 229-14 Bpiding 3229-39 McCormick 229-14 Vines 229-39 Bates 229-39 Williamson 229-14 Kramer 229-39 FRANKLIN T. GARRETT, Primary Examiner, EARLE J. DRUMMOND, Examiner. 

3. A ONE-PIECE CARDBOARD BLANK FOR FORMING A SHOCKPROOF CONTAINER FOR A FRAGILE ARTICLE; SAID BLANK COMPRISING A BOX DEFINING FIRST SECTION INCLUDING FOUR FOLDABLY CONNECTED, SUBSTANTIALLY RECTANGULAR SIDE WALL FORMING PORTIONS IN SIDE-BY-SIDE RELATIONSHIP, END CLOSURE FORMING FLAPS EXTENDING FOLDABLY FROM THE ENDS OF CERTAIN OF SAID SIDE WALL FORMING PORTIONS, AND AN ELONGATED NARROW PORTION EXTENDING ALONG ONE SIDE OF SAID BOX DEFINING SECTION AND FOLDABLY JOINED TO THE ADJACENT SIDE WALL FORMING PORTION OF THE LATTER; AND A SECOND SECTION FOR DEFINING A CUSHIONING STRUCTURE EXTENDING FOLDABLY FROM SAID ELONGATED NARROW PORTION OF THE BOX DEFINING FIRST SECTION AND INCLUDING TWO FOLDABLE, RECTANGULAR WALL DEFINING PORTIONS, A CONNECTING PORTION INTERPOSED BETWEEN SAID TWO WALL DEFINING PORTIONS AND FOLDABLY JOINED TO THE LATTER AND A FLAP DEFINING PORTION AT THE SIDE OF SAID SECOND SECTION REMOTE FROM SAID FIRST SECTION; EACH OF SAID TWO WALL DEFINING PORTIONS HAVING A CENTRAL, LONGITUDINALLY EXTENDING CUT AND TRANSVERSE CUTS AT THE ENDS OF LONGITUDINAL CUT TO DEFINE TWO OPPOSED, ELONGATED FLAPS ADAPTED TO BE STRUCK FROM THE RELATED WALL DEFINING PORTION; AND EACH OF SAID TWO WALL DEFINING PORTIONS FURTHER HAVING SHORT CUTS EXTENDING LONGITUDINALLY FROM THE ENDS OF AT LEAST ONE OF SAID TRANSVERSE CUTS AND A GENERALLY U-SHAPED CUT BETWEEN SAID SHORT CUTS AND EXTENDING IN THE DIRECTION TOWARD SAID ONE TRANSVERSE CUT TO DEFINE A TAB ADAPTED TO BE STRUCK FROM THE RELATED WALL DEFINING PORTION FOR MOVEMENT ANGULARLY WITH, BUT IN THE OPPOSITE DIRECTION FROM THE PART OF THE WALL DEFINING PORTION LOCATED BETWEEN SAID SHORT CUTS. 